In manufacturing semiconductor devices, semiconductor wafers to be processed (hereinafter, referred to as wafers) are subjected to various processes, such as film formation, oxidation, diffusion, modification, and removal of a native oxidation film. These processes are performed in a vertical type substrate processing apparatus, in which a plurality of wafers generally can be processed in a batch fashion.
Recently, a low temperature is required when a substrate process is performed. Thus, a plasma processing apparatus, in which a variety of processes can be performed even when a wafer temperature is low in the processes, has been proposed. For example, a substrate processing apparatus, in which a plurality of wafers can be plasma-processed in a batch fashion using inductively coupled plasma, has been disclosed.
In such a substrate processing apparatus, since a reaction such as film formation can be facilitated with assistance of plasma, a desired plasma processing can be performed even if a wafer temperature is relatively low.
However, in this substrate processing apparatus, a plasma generating electrode obtains a high voltage when plasma is generated at a high frequency. On this account, an electric field having a high potential difference occurs between the electrode and a wafer. This electric field also generates plasma, which damages the wafer, specifically an edge of the wafer, and thereby generates particles.